Apparent Motion

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Apparent motion is the appearance that celestial objects move due to the motion of Earth. If all the objects that appear in the sky are moving similarly, then it is far more likely that the movement is only apparent and caused by the motion of the observer.

Flat-Earthers claim that the motion of celestial objects “proves” that Earth is stationary, and the celestial objects are moving. By the same “reasoning,” we can conclude that the train we are in is stationary, it is just all the objects outside, as luck would have it, are moving in a very similar fashion.

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Apollo Astronauts and the Demand to Swear on the Bible

In the early 2000s, an unscrupulous Moon landing denialist lured Apollo astronauts into an audience with him under false pretenses. Then he insulted them as liars and pressed them to swear on the Bible that they went to the Moon.

Flat-Earthers use this incident as “evidence” that we never went to the Moon. In reality, the offender did not meet the astronauts with the best of intentions. This incident tells us more about the offender than it does about the astronauts.

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Coriolis Effect Misconception & Strawman Argument

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The Coriolis effect acts on an object that is launched to another location closer to or farther from Earth’s axis of rotation. The object retains the inertia from the surface it was launched from, but it no longer matches what is required to keep it moving in a straight line, according to an observer on the surface.

On the equator, Earth’s surface is moving at a speed of 465 m/s. Flat-Earthers assert that if that is the case, then an object launched upward should move away from the observer at the same speed. It does not happen, and they use it to disprove the Coriolis effect and Earth’s rotation in general. In reality, the Coriolis effect is not what they describe.

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Stellar Aberration

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Stellar aberration is the apparent shift of stars about their actual positions, depending on the direction Earth is moving in its orbit around the sun. It occurs because the speed of light is finite; it takes time for light to reach the observer.

Stellar aberration was discovered in 1727 by James Bradley. It was the first direct proof of heliocentrism, that Earth is in orbit around the sun.

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Mars One

Mars One was a questionable organization that received investments by claiming it would use it to land humans on Mars. It was not a credible company, and many consider it was a scam to take money from investors and participants.

Mars One had a lot of media attention, but it was dissolved without any achievement. Flat-Earthers use it to discredit space travel. In reality, the company was not credible in the first place, and practically nobody in the aerospace industry thought Mars One was serious in their objective.

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Flat-Earthers’ Alternative Facts for Gravity

Flat-Earthers reject gravity because it does not support the flat Earth model. To explain the various phenomena explained by gravity, they invented many different ‘alternative facts’ in place of gravity.

Flat-Earthers agree only on a single thing that the Earth is flat. However, as flat Earth is not fact-based, flat-Earthers cannot agree on practically everything else. Different flat-Earth denominations have their alternative explanations for gravity, all of which lacks predictive power and cannot adequately explain real-world facts.

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Umbra, Penumbra, and Antumbra in an Eclipse Diagram

Light generally travels in a straight line. We can use this property of light to determine the umbra, penumbra, and antumbra part of a shadow by drawing lines from the edges of the light source toward and past that of the occluding object.

Flat-Earthers regard the lines in an eclipse diagram as a violation of the fact that a light source emits light in every direction. In reality, the lines are there only to determine the boundaries of the shadow’s regions in an eclipse diagram.

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Stellar Parallax

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Stellar parallax is the apparent shift of the position of a nearby star against the background of distant stars. It is the result of Earth’s orbital motion around the Sun. It is tiny and difficult to observe. Successful measurement of stellar parallax was done only after the 19th century.

Some flat-Earthers claim that stellar parallax has never been successfully observed, and they use it as ‘evidence’ Earth is stationary. In reality, stellar parallax has been successfully measured in 1838 and is now used as the basis for measuring stellar distances.

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Distortion of Greenland on Maps

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Greenland is 1/14th the size of Africa. However, in a map with the Mercator projection, it appears the same size due to the distortion characteristics of the Mercator projection.

Flat-Earthers claim the distortion of the Mercator map is a failure of science to describe the world. In reality, distortion is a consequence of flattening a 3D shape into flat 2D media. Distortion also occurs with the azimuthal equidistant map, which is claimed by flat-Earthers as the so-called “flat-Earth map.” All maps have distortions: it is incorrect to assume the azimuthal equidistant map is distortion-free.

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Airplanes Will Never Fly Into Space

An airplane relies on the lift from its wings, which depends on the airplane’s speed and the air density. As a result, a cruising airplane will fly at a constant altitude, following the curvature of the Earth.

Flat-Earthers claim if Earth is a sphere, an airplane has to dip its nose down periodically, or it would fly into space. In reality, an aircraft will follow Earth’s curvature and is unable to fly to space even if the pilot deliberately attempts to do that

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Global Conspiracy Smoke and Mirrors

Some flat-Earthers use the so-called global conspiracy as an ‘escape hatch’ to abandon a losing argument. When being cornered, some flat-Earthers will tell us that flat Earth is a work in progress; it is normal for it to be incomplete, for now. “But the most important thing is to uncover the global conspiracy and save the world from these unscrupulous few!”

In reality, the global conspiracy theory is only one of so many concepts invented to prevent flat Earth from being falsified.

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“Mouse” on a SpaceX Falcon9 Rocket Launch

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In the video of the CRS-19 mission of the SpaceX Falcon9 rocket, flat-Earthers noticed something is moving near the exhaust of the second stage rocket. Creatively, they interpreted it as a “mouse, ” and then use it to discredit spaceflight and the people involved in it.

In reality, it was merely crystallized waste from the rocket engine. To know this, we only need to see the part of the video after the one cherry-picked by flat-Earthers. The “mouse” slowly disappeared by evaporation.

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Curved Appearance of a Rocket Trajectory

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Rocket launches have a curved trajectory because their objective is not only to reach space but also to enter Earth orbit. To achieve it, a spacecraft needs to gain a sufficient horizontal speed, parallel to Earth’s surface.

Flat-Earthers claim the curved appearance of a rocket launch trajectory “proves” rockets never reach space. In reality, it is caused by the motion of the rocket parallel to Earth’s surface, perspective effect, and the curvature of the Earth.

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Rocket Staging

Rockets consist of several stages. Two or more smaller rockets are combined into a single rocket. They are ignited in order; when an earlier stage runs out of propellants, it is jettisoned to reduce the load for the rest of the rocket.

Flat-Earthers noticed videos of rockets being recovered from the ocean and use them as “evidence” rockets never went to space. In reality, these are the jettisoned earlier stages of the rockets. The latter stages do reach space.

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Fiber-Optic vs Satellite Communication

Fiber-optic communication is a method of transmitting data by sending pulses of light through an optical fiber. These days, the majority of data communication involves a fiber-optic connection. However, other methods of transmitting data exist, including satellites.

Flat-Earthers use the prominence of fiber-optic communication as “proof” of the nonexistence of satellites. Such reasoning is a fallacy of hasty generalization. By the same “logic,” we can “prove” trains do not exist just by showing the existence of cars.

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Big Lie

The big lie is the propaganda method where an outrageous lie —like flat Earth— is said and repeated as if it is true, hoping people will assume it is true for granted rather than critically questioning it.

Even though anyone can easily verify that Earth is a sphere from simple personal observations, many still fall for the notion of a flat Earth. The reason is that it is such a big lie and does not fit their model of modest deception, so they think “it must be true.”

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Geostationary Satellites

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If a satellite is placed in an orbit 35786 km above the equator, it will be in motion at the same speed as the Earth’s rotation. As a result, the satellite will appear practically motionless from an observer on Earth’s surface. Many communication satellites are in this orbit so that a satellite receiver does not need to track the satellite continuously.

Flat-Earthers often take the fact that satellites are in motion, and most satellite dishes have a fixed direction as ‘proof’ the receivers cannot be pointing to satellites. In reality, it is possible to place a satellite in a geostationary orbit to make it appear in a fixed position in the sky relative to an observer on Earth.

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